Gaseous electric discharge device



May-l4, 1940- w. UYTERHOEVEN ETAL GASEOUS ELECTRIC DISCHARGE DEVICEFiled April 18, 19:55

' INV ENTbRS ATTORNEY Patented May 14, 1940 UNITED STATES PATENT OFFICEGASEOUS ELECTRIC DISCHARGE DEvIcE Application April 18, 1935, Serial No.17,082 In the Netherlands April 19, 1934 3 Claims.

The present invention relates to gaseous electric discharge devicesgenerally and more particularly the invention relates to such devicesthe container of which has two or more parallel parts and which is at anelevated temperature, such as 200 C. or more, during the operation ofthe device. Such lamps usually contain the vapor of a diflicultlyvaporized metal, that is a metal the vapor pressure of which at atemperature of 200 C. is less than 1 mm., such as sodium,-

cadmium, magnesium, or zinc.

In the United States Patent Number 2,001,511, granted May 14, 1935, alamp unit is disclosed which comprises a gaseous electric discharge lampdevice the. elongated container of which is bent into four parallel,adjacent parts. The advantage in the structure is that it is more easilymounted in lamp units comprising the lamp and a heat conservatorthereof. we have observed that when the ends of such folded lampcontainers are rigidly fastened in a common base the container is apt tobreak due to the expansion and contraction thereof under the servicecondi tions of the lamp.

The object of the present invention is to provide a lamp unit comprisinga heat conservator and a gaseous electric discharge device having afolded container in which there is no possibility of the lamp containerbreaking due to the expansion and contraction thereof under serviceconditions of the lamp. Another object of the invention is to provide alamp unit of the above type which is easily assembled and taken apart.Another object of the invention is to facilitate the starting of thegaseous electric discharge lamps in such lamp units. Still furtherobjects and advantages attaching to the device and to its use andoperation will be apparent to those skilled in the art from thefollowing particular description.

The invention attains its objects by fastening the supporting base forthe container of the gaseous electric discharge lamp at a part of saidcontainer between the ends thereof, leaving the ends of the containerfree to move when the container expands and contracts under the serviceconditions of the lamp, and by utilizing an element of the base as anauxiliary electrode to facilitate the starting of the lamp.

In the drawing accompanying and forming part of this specification anembodiment of the invention is shown in which.

Fig. 1 is a front elevational partly sectional view of a lamp embodyingthe invention,

Fig. 2 is a sectional view along the line 2-2 of Fig. 1, and

Fig. 3 is a side elevational, partly sectional view of the lamp shown inFig. 1.

Like numbers denote like parts in all the figures.

Referring to the drawing the new and novel lamp comprises an elongatedcontainer bent into four parallel parts and having an electrode 3, lsealed into'each end thereof. Each of said electrodes 3, l consist of anelement 3 which is electron emittingwhen heated and which consists of acoiled tungsten filament having another filament, such asa tungsten or anickel filament, wrapped around it. Said element 3 is coated orimpregnated with an electron emitting material, such as barium oxide.Said element 3 is surrounded by anopen ended, sheet metal cylinder 4which is electrically connected thereto. Said container I has a gaseousatmosphere therein consisting of a mixture of a starting gas, such as amixture of neon to which is added a small percentage of argon, and ametal vapor, such as sodium vapor. A small quantity of sodium isintroduced into said container I during the manufacture of the lampwhich is the source of the sodium vapor during the operation of thelamp. The container I must be at an elevated temperature during theoperation of the lamp in order to obtain an effective metal vaporpressure therein and a heat conservator, such as a double walled jackethaving the space between the walls thereof evacuated, which conservatorsurrounds the lamp container and reduces the heat losses therefrom, isuseful for this purpose. During the operation of the lamp the lightemitted thereby is rich in rays characteristic of the sodium vapor.

A base 5 of heat resisting, insulating material, such as porcelain, isfastened to a curved part of the container I at approximately the curvedmid-part of said container I. The base 5 is fastened to said container Iby the clamping element 6, I, I. The part 6 of said clamping element 6,I, 8 is a rigid body of conducting material,' nickel, for example, whichfits the curvature of the container I on one side thereof. The otherside of said part 6 fits into an indentation in the base 5. The part 1of the clamping element 6, I, 8 is flexible and is attached at one endthereof to the part 8. The other end of said flexible part I isremovably attached to the other end of the part 6 by the screw bolt 8.Said part 1 passes around the container I and clamps said container Iagainst said part 6. A thin layer of heat resisting, insulatingmaterial, such as asbestos, is interposed between the container I andsaid part I. Said part 6 has fastenedthereto a metal pinIO which passesthrough an opening in the base and which is threaded. Said clampingelement 6, I, 8 is fastened to said base 5 by the nut II which pulls upand holds the pin I0 in position on the base 5.

The element 6 also serves as an auxiliary electrode having a capacitiveaction for facilitating the starting or the gaseous electric dischargedevice. The pin I 0 is a contact element for the auxiliary electrode 6.i In order to avoid the presence of air bubbles between the auxiliaryelectrode 6 and the wall of the container I the part 0! the wall coveredby said electrode 6 is coated, by methods well known in the art, as bythe Schoop method. for example, with a thin layer I3 of metal (Fig. 1).This avoids the creation of an electric field in the space between thelayer l3 and the electrode 6 and prevents ionization of the air in thisspace.

The electrodes 3, 4 of the lamp are connected by flexible leads I4 tothe contact pins 12 of the base 5. Said leads H are removably connectedto said contact pins I2. The flexible leads I permit the ends 2 of thecontainer I to move when the container I expands and contracts under theservice conditions or the lamp.

A suitable heat conservator (omitted from the drawing for simplicity ofillustration) is a double walled jacket surrounding the container I andhaving the space between the walls thereof evacuated. Said conservatoris provided with a supporting ring of heat resisting material, such asporcelain, cemented thereto and which ring makes a tight mechanicaljoint with the shoulder of the base 5.

The lamp unit is easily assembled by inserting the container l in theclamp 6, I, 8, tightening the bolt 8, attaching leads I 4 to the pins I2and slipping the supporting ring of the heat conservator onto the base5. The lamp unit is just as easily taken apart. The ends 2 of the lampdevice are free to move when the container I expands or contracts sothat the danger of the container walls breaking is obviated. The lamp isquickly started into operation by the auxiliary electrode 6 mountedalong the discharge path between the electrodes 3, 4.

While we have shown and described and have pointed out in the annexedclaims certain novel features of the invention, it will be understoodthat various omissions, substitutions and changes in the forms anddetails'of the device illustrated and in its use and operation may bemade by those skilled in the art without departing from the broad spiritand scope of the invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. A lamp unit comprising in combination a gaseous electric dischargelamp device, a base therefore, and a clamp of electrically conductingmaterial, said lamp comprising an elongated, curved container, said basebeing removably fastened to said container between the ends of saidcontainer by said clamp, the ends of said container being free to movewith respect to the other elements of said lamp unit.

2. A lamp unit comprising in combination a gaseous electric dischargelamp device, a base therefor, and a clamp of electrically conductingmaterial, said lamp comprising an elongated, curved container, said basebeing removably fastened to said container between the ends of saidcontainer by said clamp, said clamp being an auxiliary electrode tofacilitate the starting or said lamp, and a body of heat insulatingmaterial interposed between the movable part 01 said clamp and saidcontainer, the ends of said container being free to move with respect tothe other elements of said lamp unit.

3. A lamp unit comprising in combination a gaseous electric dischargelamp device and a base therefor, and a clamp of electrically conductingmaterial, said lamp comprising an elongated, curved container, said basebeing removably fastened to said'container between the ends of saidcontainer by said clamp, said clamp being an auxiliary electrode tofacilitate the starting of said lamp, said container having a metalcoating on the outer surface thereof in contact with the immovable partof said clamp, the ends of said container being free to move withrespect to the other element of said lamp unit.

JOHANNES P. M. MUTSAERS. WILLEM UYTE'RHOEVEN. CORNELIS VERBURG. PIE'I'ERSCHOUWS'I'RA.

CERTIFlCATE OF CORRECTION.-

,Patent No. 2,200,9LLQ. u may 1h, 19h0.

WILLEM UYTERHOEVEN, ET AL.

It is hereby certified that errorappears in the printed specification ofthe above numbered patent requiring correction as follows: Page 1 firstcolumn, line 8, for the'vilord "vaporized" read --vaporiz'gble--; page2, second column, line 15, claim 5, for "element" read -elementS- andmay the saiid Letters Patent shculd be read with. thiscorrection,therein that the same may conform to the record-of the casein the Patent Office.

Signed and sealed this 14.1:11 day of March, A, D. 19141.

Henry Van Arsdale, (86211)" Acting Commissioner cf Patents.

